Locomotive valve gear



April 1930-- C. J. SCUDDER 1,753,028

LOGOMOTIVE VALVE GEAR Filed Sept. 25, 1927 Patented Apr. 1, 1930 usatzs Artur orsicri CHARLES J. SCUDDER, F SGRANTON, PENNSYLVANIA LOCOMOTIVE VALVE GEAR Application filed September 2 3, 1927. SerialNo. 221,580.

My invention relates to locomotive valve gears, more particularly to apparatus for as sociation with locomotive valve gears, and has for its object the provision of apparatus of the character designated which shall be efiective to automatically indicate to the operator, or engineman, the point of most economical cut off of the valves. I

A more specific object of my invention is 10 to provide a cut oif limiting device which shall be eifective to automatically limit the cut off of the locomotive valves to a predetermined economical range, and which shall yieldingly resist movement of the cut off 1 varying mechanism of thevalve gear in a direction for increasing the cut ofi beyond said range.

A still further object of my invention is to provide a simple, effective cut oif limiting device adapted to be associated with the reverse lever of a locomotive for yieldingly resisting movements of the lever in a direction for increasing the cut off of the valves beyond a desired point and which shall require manual holding of the lever in positions to efi'ect a longer cut off than that determined by said point. i

As is well known in the art to which my invention relates, it is always economical to work'steam expansively. A given amount of steam with a ratio of expansion of 4 Willdo more than twice as much work in the cylinders of a locomotive as the same amount of steam with a ratio of expansion of 1. It

has also been found that the point atwhich steam should be expanded to obtain the greatest economy may not be the same in any two engines, but must be determined for each engine. Ihave found, furthermore, that higher steam pressure than has heretofore been commonly used with a locomotive of a given weight may be employed, thus increasing the tractive effort and decreasing the factor of adhesion of the locomotive without danger of slipping, provided that intelligent manipulation of the cut off of the locomotive valves be had at starting.

In order to provide means whereby the well known economies of working steam expansively may be availed of by the engineman,

regardless of his acquaintance with the particular locomotive or his tendency to do otherwise, and in order to increase the tractive effort of a locomotive for a given weight upon drivers and insure proper manipulation of such a locomotive in starting, 1 have provided a simple efiective device which may be readily attached to the reverse lever or to the reverse lever quadrant, and which is adapted to automatically be engaged and yieldingly resist movements of the reverse lever beyond a desired maximumcut off point when the reverse lever is being moved in a direction to lengthen the out OK. In the preferred embodiment of my invention, herein 6 described, it comprises a spring abutment carried by the reverse lever and adapted to engage suitable stops both at the front and the rear ends of the quadrant. V The stops are so.

positioned that the abutment is engaged at the point of desired cut off of the valves. In order for the engineman to lengthen the cut ofi beyond that point, he must overcome the resistance of the spring. Furthermore, in order to insurethat the locomotive will not be worked longer than is absolutely necessary at points of lengthened cut oif, beyond the economical point, Iblank off the quadrant beyond the economical point so that not only i must the resistance of the spring be overcome,

but the reverse lever must be held in the increased cut off position as long as it "is to relever and quadrant equipped with my invention; and

Fig. 3 is a view similar to Fig. 2, but show- 9 ing a modified form of my invention. Referring now to'the drawing for a better understanding of my invention, I show a locomotive cylinder 10 having a piston 11 and a valve 12 for controlling the distribution of steam to the cylinder. The valve 12 is actuated by a radius rod 13 through a combination lever 14 and cross head 15, the lever 14 having its action modified by the locomotive cross head 16 through a link 17. The radius rod 13 connects with a sliding link block 18 fitting in a link 19 pivoted at 20. Connected to the lower end *(DfllZhB link 19 is .an eccentric rod 21 driven from the locomotive driving wheel and adapted to impart reciprocatory motion to the lower end of the link 19. When the block 18 is at the lower end of the link 19, as seen in the drawing, the valves are set for forward motion and steam is admitted to the cylinder 10 the full length of the stroke of the piston. If the radius rod 13 be raised so as to cause the block 18 to approach the pivot 20, the travel of the valve 12 decreases and cuts off the steam from the cylinder at shorter periods in the stroke of the piston 11. If the block 18 be raised to the upper end of the link 19, it effects a reversal of the motion of the engine and admits steam to the cylinder for the full travel of the piston 11. If the block 18 be lowered from its extreme upper position so as to approach the pivot 20, steam is admitted to the cylinder at shorter periods in the piston stroke, thus effecting a shortened ordecreasedcut 01f of the valve.

The valve gear just described is the well known Walschaert type and is described for illustrative purposes only. :It will be apparent, from a further description of my invention, that it is equally applicable to any type of locomotive valve gear wherein the cut off of the valves is variable.

In order to accomplish the cut ofi function just described, the locomotive is provided with a reverse lever 26 having a quadrant 27, and, in the example shown in Figs. 1 and 2, being pivoted at 28. The lower end of the reverse lever 26 is connected to a reach rod 29 and the latter is connected to a bell crank lever 31. The bell crank lever 31 is pivoted at 32' and connects through a link .33 with the radius rod 13.

As is well understood when the reverse lever is moved to its extreme position forward, as is shown in Fig. 1, the block 18 is at the lower end of the link with the valve cut off at full stroke of the piston. 'When the reverse lever is at the extreme backward end of the quadrant 27, the block 18 is .at the upper end of the .link 19 with the valve gear reversed and with the cut off at full stroke of the piston 11.

Referring now to Fig. .2, the quadrant 27' valve 12 in forward and reverse motion, respectively. Beyond the notches 38 and 39 the quadrant is left blank. Secured to the reverse lever 26 are a pair of cylindrical members 41 and 42 which may be secured together by cooperating flanges 43 and 44, held together by a bolt 46. Within the members 41 and 42 is a spring 47 which bears, atits two ends, against a pair of cylindrical members 48 and 49, fitting within the members 41 and 42 and extending outwardly therefrom. The members 48 and 49 are provided with heads 51 and 52 which cooperate with flanges at the ends of the members 41 and 42 and prevent their moving'outwardly beyond a predetermined distance. Secured to the ends of the quadrant 27, and in such position as to engage the members 48 and 49, are stops 53 and 54. The stops 53 and 54 are so disposed that they engage the members 48 and 49 when the reverse lever is in the notches 39 and 38, respectively. In order to move the reverse lever in a direction to lengthen the cut off of the valve 12 beyond that determined either by the notch 38 or the notch 39, it is necessary forthe engineman to overcome theforce exerted by the spring 47, which force is made suflicient to normally hold the reverse lever against movement. There being no notches on the guadrant 27 for a cut off longer than that etermined by the notches 38 and 39, it will be necessary for the engineman, whenhe desires to operate the locomotive with longer cut off, to hold the reverse lever in a position for such longer cut off against the tension of r the spring 47.

In Fig. 3, I show another embodiment of my invention wherein a spring abutment comprising a cylindrical member 56 is secured to the quadrant 27 at each end thereof and has disposed therein a spring 57. Fitting into the member 56 is a second cylindrical member-58, the spring 57 acting to hold the two members extended. A bolt 59 extends through the members 56 and 58 and limits the outward movement of the member 58. In this embodiment, when the lever 26 is moved forward to the notch '38, it engages the member 58 and further movement in a direction for lengthening the cut off of the valve is resisted by the spring 57. N o notches notch 38, for lengthened out off, the engineman must hold the reverse lever against the tension of the spring 57. Likewise, when the reverse lever is moved toward the rear end of the quadrant 27 to the notch 39, it engages the member 58 at the rearward end and further movement is resisted in the same mainner as was described for the forward en V In both embodiments of my invention, I have shown, as a preferred means of carrying out my invention, spring pressed means for yieldingly resisting movements of thereverse lever beyond a desired maximum point of cut off. It will be obvious, however, to those skilled in the art, that a wide variety of suitable yielding means might be substituted for the spring, and it must be understood that my invention is not so limited.

From the foregoing it will be apparent that I have devised an improved cut ofi limiting device for association with locomotive valve gears, which is simple and eflective and which may be readily applied to any existing type of locomotive valve gear.

While I have shown my invention in but two forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claim.

What I claim is:

The combination with a locomotive valve gear including a reverse lever for varying the cut ofi? of the valves, and a quadrant for the reverse lever having notches for latching said lever so as to hold it at desired oints of cut off, of yieldable abutments carried by the reverse lever and extending forwardly and rearwardly thereof for resisting movement of the lever in a direction to effect maximum out ofi, a stop for each abutment secured to each end of the quadrant, said stops being so located as to be engaged during movements of the lever toward lengthened cut off positions and toyieldingly position the lever at desired normal cut ofi, said quadrant being blank for positions of cut off longer than the desired normal operating out f OK.

In testimony whereof, I have hereunto subscribed my name this 17th day of September, 1927.

' CHARLES J. SCUDDER. 

